TY - JOUR
T1 - Metal mobilization and production of short-chain organic acids by rhizosphere bacteria associated with a Cd/Zn hyperaccumulating plant, Sedum alfredii
AU - Li, W. C.
AU - Ye, Z. H.
AU - WONG, Ming Hung
N1 - Funding Information:
Acknowledgments The authors would like to thank Prof. Norman Terry (University of California, Berkeley) for the provision of bacterial strains, Prof. P.Y. Qian (Hong Kong University of Science & Technology) for the bacteria identification and Ms. Ursula Absalom for improving the manuscript. Financial support from the Research Grants Council of the University Grants Committee of Hong Kong and Area of Excellence (CityU/AoE/03-04/02) are gratefully acknowledged.
PY - 2010/1
Y1 - 2010/1
N2 - Sedum alfredii, a cadmium (Cd) and zinc (Zn) hyperaccumulator at a mine located in Qu Zhou City, Zhejiang Province, China, can accumulate Cd and Zn exceeding 1,000 and 10,000 mg kg -1, respectively in its shoot (dry weight) when growing under metal-contaminated habitats. Several strains of bacteria were isolated from the rhizosphere of S. alfredii thriving in different Pb/Zn mines in Hunan Province and Zhejiang Province, China, which can resist high levels of heavy metals. Among the different strains isolated, Burkholderia cepacia showed the highest ability in mobilizing Cd and Zn as well as resisting high concentrations of soluble Zn (500 mg L -1). The soluble Zn concentration in the medium increased from 13 to 72 and 99% (p < 0.001) after bacterial inoculation in the medium supplemented with insoluble zinc oxide and zinc carbonate, respectively, while pH dropped from 7 to 2.93. The soluble Cd concentration was also increased from 8 to 96% (p < 0.001), and pH decreased from 7 to 2. 65. Short-chain organic acids were also analyzed and the results indicated that oxalic acid, tartaric acid, formic acid and acetic acid had a significant correlation (p < 0. 001) with the concentrations of Cd and Zn being mobilized during the assay. The present results implicated that certain bacteria associated with metal hyperaccumulators could contribute significantly in mobilizing heavy metals, which would enhance the phytoextraction process.
AB - Sedum alfredii, a cadmium (Cd) and zinc (Zn) hyperaccumulator at a mine located in Qu Zhou City, Zhejiang Province, China, can accumulate Cd and Zn exceeding 1,000 and 10,000 mg kg -1, respectively in its shoot (dry weight) when growing under metal-contaminated habitats. Several strains of bacteria were isolated from the rhizosphere of S. alfredii thriving in different Pb/Zn mines in Hunan Province and Zhejiang Province, China, which can resist high levels of heavy metals. Among the different strains isolated, Burkholderia cepacia showed the highest ability in mobilizing Cd and Zn as well as resisting high concentrations of soluble Zn (500 mg L -1). The soluble Zn concentration in the medium increased from 13 to 72 and 99% (p < 0.001) after bacterial inoculation in the medium supplemented with insoluble zinc oxide and zinc carbonate, respectively, while pH dropped from 7 to 2.93. The soluble Cd concentration was also increased from 8 to 96% (p < 0.001), and pH decreased from 7 to 2. 65. Short-chain organic acids were also analyzed and the results indicated that oxalic acid, tartaric acid, formic acid and acetic acid had a significant correlation (p < 0. 001) with the concentrations of Cd and Zn being mobilized during the assay. The present results implicated that certain bacteria associated with metal hyperaccumulators could contribute significantly in mobilizing heavy metals, which would enhance the phytoextraction process.
KW - Burkholderia cepacia
KW - Hyperaccumulating plant
KW - Metal tolerant bacteria
KW - Phytoextraction
UR - http://www.scopus.com/inward/record.url?scp=72149094038&partnerID=8YFLogxK
U2 - 10.1007/s11104-009-0025-y
DO - 10.1007/s11104-009-0025-y
M3 - Journal article
AN - SCOPUS:72149094038
SN - 0032-079X
VL - 326
SP - 453
EP - 467
JO - Plant and Soil
JF - Plant and Soil
IS - 1
ER -